Which of the following is a part of the upper extremity?

The shoulder girdle is a key component of the upper extremity, connecting the upper limbs to the trunk of the body. It consists of the clavicles and scapulae, providing attachment points for several muscles and allowing for a range of motions in the arms. This structure supports the upper limb and plays a crucial role in activities that involve movement such as lifting, reaching, and throwing.

In contrast, the pelvis relates to the lower extremity and serves as the connector between the lower limbs and the spine. The leg consists of the thigh, knee, calf, and foot, which are all parts of the lower extremity. The vertebral column, or spine, comprises the series of vertebrae that protect the spinal cord and supports the upper body, but it does not directly relate to the upper extremity. Thus, the shoulder girdle is distinctly associated with the upper extremity, emphasizing its importance in this anatomical classification.